A false report showed up on CNN's iReport claiming Apple founder Steve Jobs had suffered a major heart attack. Proof that whether you call it "citizen" journalism or blogging or the next best thing in news, you still have to do the basics - like fact-checking.
UPDATE: Another basic, as Ken Doctor at Content Bridges points out, is labeling what is news and what is opinion. However, I don't think Doctor fully takes into account the uncontrollable urge CNN and other mainstream media outlets have in blurring the lines between commentary, opinion and news. They called it iReport because they wanted readers and contributors to consider the content as some form of journalism. The blurred line gives CNN more hits without much expense and gives the company some street cred in the world of "citizen" journalism. To use an economic metaphor, CNN wanted to benefit from the upside while minimizing the risk on the downside. We all see how well that worked in the housing market.
UPDATE II: Wired.com speculates as to whether the author of the erroneous iReport could get prison time.